Automatic electric toolholding switch



Jun 29, 1948. E. H. ENGLUND 2,444,188

AUTOMATIC ELECTRIC TOOL HOLDING SWITCH Filed NOV. 6, 1944 2 Sheets-Sheetl .EJZZ-.EI Zzznd 1 69.1 iVl ENTOR.

BY Z a 4 Z June 29, 1948; E H G ND 2,444,188

AUTOMATIC ELECTRIC TOOL HOLDING SWITCH Filed. Nov. 6, 1944' 2Sheets-Sheet 2 .AL I

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Patented June 29, 1948 UNITED STATES FATENT FFICE AUTUMATIG ELECTRICTOULHOLDING SWITCH 1 Claim.

This invention relates to automatic electric switch construction, andaims to provide a novel form of switch for use in connection withmotordriven tools such as forming a part of routing machines, the switchembodying a support for the tool which actuates the switch to break thecircuit to the motor providing the power for operating the tool, whenthe tool has been placed on the support, the Weight of the tooloperating the switch as described.

With the foregoing and other objects in View which will appear as thedescription proceeds, the invention consists of certain novel details ofconstruction and combinations of parts hereinafter more fully describedand pointed out in the claim, it being understood that changes may bemade in the construction and arrangement of parts without departing fromthe spirit of the invention as claimed.

Referring to the drawings Figure 1 is an elevational view of a routingmachine, equipped with an automatic switch constructed in accordancewith the invention.

Figure 2 is a side elevational view thereof.

Figure 3 is a modified form of switch designed primarily for use withthe rail-type of router machines.

Figure 4 is an enlarged longitudinal sectional view through the switchand switch housing.

Figure 5 is a similar longitudinal sectional view illustrating theswitch in its open position.

Figure 6 is a sectional View taken on line t5 of Fig. 4.

Figure '7 is a. sectional View taken on line T'i of Fig. 4.

Figure 8 is an enlarged fragmental sectional view through the switchhousing, illustrating the arm which is connected with the switch formanually operating the switch.

Referring to the drawings in detail, the machine embodies a stand 5 onwhich the motor indicated at 6 is mounted, the motor being provided withthe usual motor shaft on which the pulleys 1 and 8 are mounted, theshaft and pulleys transmitting motion to the flexible shaft 9 of themachine, through the belt I and pulleys H and I2.

Rising from the motor casing, is a post 13 Which is hollow, toaccommodate the wires l4, providing the circuit between a source ofelectricity supply, and the motor.

Mounted on the upper end of the tubular post I3, is the switch housing lwhich is formed with an opening in the upper end thereof, to accommodatethe switch spindle It. This switch spindle i 6 operates through thetubular bearing H which is constructed of suitable insulating material.The bearing ll is formed with an annular flange near its upper end,against which the contact ring it rests to move with the tubular bearingl1. Secured to the switch spindle i6 is a tubular bearing I9 againstwhich the lower end of the tubular bearing l'. rests. A coiled springindicated at 26 has its upper end resting against the tubular bearingl9, the lower end thereof resting on the bracket 2| which is secured tothe inner surface of the switch housing Hi, the bracket having anopening through which the spindle I6 moves. The head 22 of the spindleI6 is adapted to move into engagement with the upper end of the bracket2!, as shown by Fig. 4 of the drawings, limiting the upward movement ofthe spindle I6 when the tool has been removed from its supporting hook.

In order that the switch may be manually operated, an arm 23 isprovided, which arm is secured to the :bearing ring l9 and extendsthrough a slot in the wall of the housing 15, there being providednotches to receive the arm 23, so that the arm and spindle may besecured in various positions of adjustment. The reference character 24indicates a knob secured to the outer end of the arm 23 to facilitatethe moving of the arm and spindle.

Mounted within the switch housing, are contact bars 25, which have theirupper ends extended inwardly, providing contact members 26 adapted to beengaged by the contact ring l8, to complete the circuit through thecontact members to the wires l4, which are shown as connected with theterminals 2'! at the lower ends of the contact bars.

The reference character 28 designates the support or hook for receivingthe tool that receives its motion through the flexible shaft 9, and thissupport or hook comprises a body portion which is secured to the machineat the upper end thereof. The support or hook 28 is formed with anopenin through which the rod 29 extends, the rod being formed with aplunger 30 at its lower end which is connected to the upper end 0f thespindle l 6, as clearly shown by the drawings.

On the upper end of the rod 29 is a head 3| that normally extends abovethe surface of the support or hook 28 so that when the tool ispositioned thereon, the tool, which in the present showing, is indicatedby the reference character A, contacts the head 3| and moves the headand rod 29 downwardly, to the position as shown by Fig. 5 of thedrawings, breaking the circuit between the bars 25 and consequentlycutting off the current to the motor.

When the tool is removed for use, the coiled spring 29 will of courseexpand, moving the member I1 and contact ring 18 to the positions shownby Fig. 4 of the drawings, completing the circuit.

Due to this construction, it will be obvious that if the tool isreturned to its support or hook, after use, the motor will beimmediately cut oil, and electric power, as well as wear and tear on themovable parts of the machine, will be reduced to a minimum.

What is claimed is:

A switch of the class described, comprising an elongated body portion,spaced elongated contact members mounted within the body portion, wiresextending into the body portion and being connected with the lower endsof the elongated contact members, said wires being in circuit with asource of electric supply, providing an electric circuit to the contactmembers, the upper ends of the contact members extending at right anglesproviding contact points, a spindle operating within the body portionand being movable between the contact points, a tubular insulatingmember on the spindle insulating the contact points from each other, acontact ring carried by the insulating material and adapted to move intoengagement with the contact points, completing an electric circuittherethrough, said contact points providing a stop for the spindle andcon tact ring restricting upward movement of the spindle and contactring, means for normally urging the spindle and contact ring towards thecontact points, said contact ring and spindle adapted to move away fromthe contact points under weight directed to the upper end of thespindle, and manually operated means for moving the spindle and contactrin to break the circuit to the contact members, holding the circuitopen. EDWIN H. L. ENGLUND.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 453,871 Stovell June 9, 18911,132,154 Bliley Mar, 16, 1915 1,150,413 Berry et a1 Aug. 17, 19151,161,477 Horton Nov. 23, 1915 1,489,459 Rees Apr. 8, 1924 2,075,244McLain Apr, 6, 1937 2,076,637 Harlow et al Apr. 13, 1937 2,121,798 HoweJune 28, 1938 2,144,858 Smith Jan. 24, 1939 2,389,259 Horlacher Nov. 20,1945

